System and method for detection of materials using orbital angular momentum signatures

ABSTRACT

An apparatus for detecting a presence of a predetermined material within a sample uses signal generation circuitry for generating a first signal having a first distinct signature including a first eccentricity of a mode intensity, a first shift in a center of the mode intensity and a first rotation of an ellipsoidal intensity output of the mode intensity and applying the first signal to the sample. A detector receives the first signal after the first signal passes through the sample and detects a second distinct signature including a second eccentricity of the mode intensity, a second shift in the center of the mode intensity and a second rotation of the ellipsoidal intensity output of the mode intensity. The detector also determines the presence of the predetermined material within the sample based on the detected second distinct signature within the first signal received from the sample and provides an output of an indication of the presence of the predetermined material responsive to the determination.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/942,641, filed Nov. 16, 2015, entitled SYSTEM AND METHOD FORDETECTION OF MATERIALS USING ORBITAL ANGULAR MOMENTUM SIGNATURES, whichclaims benefit of U.S. Provisional Application No. 62/081,846, filed onNov. 19, 2014, entitled DISTINCT SIGNATURES FOR CONCENTRATIONMEASUREMENTS, the specifications of which are incorporated by referenceherein in their entirety.

U.S. application Ser. No. 14/942,641 is also a Continuation-in-Part ofU.S. application Ser. No. 14/339,836, filed on Jul. 24, 2014, entitledSYSTEM AND METHOD FOR MAKING CONCENTRATION MEASUREMENTS WITHIN A SAMPLEMATERIAL USING ORBITAL ANGULAR MOMENTUM, now U.S. Pat. No. 9,267,877,issued Feb. 23, 2016, which published on Sep. 17, 2015, as U.S.Application Publication No. 2015-0260650. This application is also aContinuation-in-Part of U.S. application Ser. No. 14/875,507, filed onOct. 5, 2015, entitled SYSTEM AND METHOD FOR EARLY DETECTION OFALZHEIMERS BY DETECTING AMYLOID-BETA USING ORBITAL ANGULAR MOMENTUM.U.S. application Ser. Nos. 14/339,836 and 14/875,507, and U.S.Application Publication No. 2015-0260650 are incorporated by referencein their entirety.

TECHNICAL FIELD

The present invention relates to the detection of materials within asample using orbital angular momentum (OAM), and more particularly, tothe detection of materials within a sample based upon unique signaturesof orbital angular momentum imparted to a signal passing through thesample.

BACKGROUND

Concentration measurements and detection of the presence of organic andnon-organic materials is of great interest in a number of applications.In one example, detection of materials within human tissue is anincreasingly important aspect of healthcare for individuals. Thedevelopment of non-invasive measurement techniques for monitoringbiological and metabolic agents within human tissue is an importantaspect of diagnosis therapy of various human diseases and may play a keyrole in the proper management of diseases. The development ofnon-invasive measurement techniques for monitoring biological andmetabolic agents within human tissue is an important aspect of diagnosistherapy of various human diseases and may play a key role in the propermanagement of diseases. One such material relevant to Alzheimer's isamyloid-beta. Thus, there is a need for an improved manner ofamyloid-beta detection to better improve detection of early stages ofAlzheimer's.

Another example of a biological agent that may be monitored for withinhuman tissue is glucose. Glucose (C₆H₁₂O₆) is a monosaccharide sugar andis one of the most important carbohydrate nutrient sources. Glucose isfundamental to almost all biological processes and is required for theproduction of ATP adenosine triphosphate and other essential cellularcomponents. The normal range of glucose concentration within human bloodis 70-160 mg/dl depending on the time of the last meal, the extent ofphysical tolerance and other factors. Freely circulating glucosemolecules stimulate the release of insulin from the pancreas. Insulinhelps glucose molecules to penetrate the cell wall by binding twospecific receptors within cell membranes which are normally impermeableto glucose.

One disease associated with issues related to glucose concentrations isdiabetes. Diabetes is a disorder caused by the decreased production ofinsulin, or by a decreased ability to utilize insulin and transport theglucose across cell membranes. As a result, a high potentially dangerousconcentration of glucose can accumulate within the blood (hyperglycemia)during the disease. Therefore, it is of great importance to maintainblood glucose concentration within a normal range in order to preventpossible severe physiological complications.

One significant role of physiological glucose monitoring is thediagnosis and management of several metabolic diseases, such as diabetesmellitus (or simply diabetes). There are a number of invasive andnon-invasive techniques presently used for glucose monitoring. Theproblem with existing non-invasive glucose monitoring techniques is thata clinically acceptable process has not yet been determined. Standardtechniques from the analysis of blood currently involve an individualpuncturing a finger and subsequent analysis of collected blood samplesfrom the finger. In recent decades, non-invasive blood glucosemonitoring has become an increasingly important topic of investigationin the realm of biomedical engineering. In particular, the introductionof optical approaches has caused some advances within the field.Advances in optics have led to a focused interest in optical imagingtechnologies and the development of non-invasive imaging systems. Theapplication of optical methods to monitoring in cancer diagnostics andtreatment is also a growing field due to the simplicity and low risk ofoptical detection methods. In addition to the medical field, thedetection of various types of materials in a variety of otherenvironments would be readily apparent.

Many optical techniques for sensing different tissue metabolites andglucose in living tissue have been in development over the last 50years. These methods have been based upon florescent, near infrared andmid-infrared spectroscopy, Raman spectroscopy, photoacoustics, opticalcoherence tomography and other techniques. However, none of thesetechniques that have been tried have proved completely satisfactory.

Another organic component lending itself to optical materialconcentration sensing involves is human skin. The defense mechanisms ofhuman skin are based on the action of antioxidant substances such ascarotenoids, vitamins and enzymes. Beta carotene and lycopene representmore than 70% of the carotenoids in the human organism. The topical orsystematic application of beta carotene and lycopene is a generalstrategy for improving the defense system of the human body. Theevaluation and optimization of this treatment requires the measurementof the b-carotene and lycopene concentrations in human tissue,especially in the human skin as the barrier to the environment.

Thus, an improved non-invasive technique enabling the detection ofconcentrations and presence of various materials within a human body orother types of samples would have a number of applications within themedical field.

SUMMARY

The present invention, as disclosed and described herein, in one aspectthereof, comprises an apparatus for detecting a presence of apredetermined material within a sample uses signal generation circuitryfor generating a first signal having a first distinct signatureincluding a first eccentricity of a mode intensity, a first shift in acenter of the mode intensity and a first rotation of an ellipsoidalintensity output of the mode intensity and applying the first signal tothe sample. A detector receives the first signal after the first signalpasses through the sample and detects a second distinct signatureincluding a second eccentricity of the mode intensity, a second shift inthe center of the mode intensity and a second rotation of theellipsoidal intensity output of the mode intensity. The detector alsodetermines the presence of the predetermined material within the samplebased on the detected second distinct signature within the first signalreceived from the sample and provides an output of an indication of thepresence of the predetermined material responsive to the determination.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding, reference is now made to thefollowing description taken in conjunction with the accompanyingdrawings in which:

FIG. 1 illustrates the manner for using an Orbital Angular Momentumsignature to detect the presence of a material within a sample;

FIG. 2 illustrates the manner in which an OAM generator generates an OAMtwisted beam;

FIG. 3 illustrates a light beam having orbital angular momentum impartedthereto;

FIG. 4 illustrates a series of parallel wavefronts;

FIG. 5 illustrates a wavefront having a Poynting vector spiraling arounda direction of propagation of the wavefront;

FIG. 6 illustrates a plane wavefront;

FIG. 7 illustrates a helical wavefront;

FIG. 8 illustrates a plane wave having only variations in the spinvector;

FIG. 9 illustrates the application of a unique orbital angular momentumto a wave;

FIGS. 10A-10C illustrate the differences between signals havingdifferent orbital angular momentum applied thereto;

FIG. 11 illustrates the propagation of Poynting vectors for variouseigenmodes;

FIG. 12 illustrates a block diagram of an apparatus for providingconcentration measurements and presence detection of various materialsusing orbital angular momentum;

FIG. 13 illustrates an emitter of the system of FIG. 11;

FIG. 14 illustrates a fixed orbital angular momentum generator of thesystem of FIG. 11;

FIGS. 15A-15D illustrate various holograms for use in applying anorbital angular momentum to a plane wave signal;

FIG. 16 illustrates the relationship between Hermite-Gaussian modes andLaguerre-Gaussian modes;

FIG. 17 illustrates super-imposed holograms for applying orbital angularmomentum to a signal;

FIG. 18 illustrates a tunable orbital angular momentum generator for usein the system of FIG. 11;

FIG. 19 illustrates a block diagram of a tunable orbital angularmomentum generator including multiple hologram images therein;

FIG. 20 illustrates the manner in which the output of the OAM generatormay be varied by applying different orbital angular momentums thereto;

FIG. 21 illustrates an alternative manner in which the OAM generator mayconvert a Hermite-Gaussian beam to a Laguerre-Gaussian beam;

FIG. 22 illustrates the manner in which holograms within an OAMgenerator may twist a beam of light;

FIG. 23 illustrates the manner in which a sample receives an OAM twistedwave and provides an output wave having a particular OAM signature;

FIG. 24 illustrates the manner in which orbital angular momentuminteracts with a molecule around its beam axis;

FIG. 25 illustrates a block diagram of the matching circuitry foramplifying a received orbital angular momentum signal;

FIG. 26 illustrates the manner in which the matching module may usenon-linear crystals in order to generate a higher order orbital angularmomentum light beam;

FIG. 27 illustrates a block diagram of an orbital angular momentumdetector and user interface;

FIG. 28 illustrates the effect of sample concentrations upon the spinangular polarization and orbital angular polarization of a light beampassing through a sample;

FIG. 29 more particularly illustrates the process that alters theorbital angular momentum polarization of a light beam passing through asample;

FIG. 30 provides a block diagram of a user interface of the system ofFIG. 12;

FIG. 31 illustrates a network configuration for passing around datacollected via devices such as that illustrated in FIG. 15;

FIG. 32 provides a block diagram of a more particular embodiment of anapparatus for measuring the concentration and presence of glucose usingorbital angular momentum;

FIG. 33 illustrates an optical system for detecting a unique OAMsignature of a signal passing through a sample under test;

FIG. 34 illustrates the manner in which the ellipticity of an OAMintensity diagram changes after passing through a sample;

FIG. 35 illustrates the manner in which a center of gravity of anintensity diagram shifts after passing through a sample;

FIG. 36 illustrates the manner in which an axis of the intensity diagramshifts after passing through a sample;

FIG. 37A illustrates an OAM signature of a sample consisting only ofwater;

FIG. 37B illustrates an OAM signature of a sample of 15% glucose inwater;

FIG. 38A illustrates an interferogram of a sample consisting only ofwater;

FIG. 38B illustrates an interferogram of a sample of 15% glucose inwater;

FIG. 39 shows the amplitude of an OAM beam;

FIG. 40 shows the phase of an OAM beam;

FIG. 41 is a chart illustrating the ellipticity of a beam on the outputof a Cuvette for three different OAM modes;

FIGS. 42A-42C illustrates the propagation due to and annulus shaped beamfor a Cuvette, water and glucose;

FIG. 43 illustrates OAM propagation through water for differing drivevoltages;

FIG. 44 illustrates an example of a light beam that is altered by ahologram to produce an OAM twisted beam;

FIG. 45 illustrates various OAM modes produced by a spatial lightmodulator;

FIG. 46 illustrates an ellipse;

FIG. 47 is a flow diagram illustrating a process for analyzing intensityimages; and

FIG. 48 illustrates an ellipse fitting algorithm.

DETAILED DESCRIPTION

Referring now to the drawings, wherein like reference numbers are usedherein to designate like elements throughout, the various views andembodiments of a system and method for detecting materials using orbitalangular momentum signatures are illustrated and described, and otherpossible embodiments are described. The figures are not necessarilydrawn to scale, and in some instances the drawings have been exaggeratedand/or simplified in places for illustrative purposes only. One ofordinary skill in the art will appreciate the many possible applicationsand variations based on the following examples of possible embodiments.

Referring now to the drawings, and more particularly to FIG. 1, there isillustrated the manner for detecting the presence of a particularmaterial within a sample based upon the unique orbital angular momentumsignature imparted to a signal passing through the sample. An opticalsignal 102 having a series of plane waves therein is applied to a devicefor applying an orbital angular momentum (OAM) signal to the opticalsignal 102 such as a spatial light modulator (SLM) 104. While thepresent embodiment envisions the use of an optical signal 102, othertypes of signals having orbital angular momentum or other orthogonalsignals therein may be utilized in alternative embodiments. The SLM 104generates an output signal 106 having a known OAM twist applied to thesignal. The OAM twist has known characteristics that act as a baselineprior to the application of the output signal 106 to a sample 108. Thesample 108 may comprise a material contained within a holding container,such as a cuvette, or may be a material in its natural state, such asthe eye or body of a patient or its naturally occurring location innature. The sample 108 only indicates that a particular material or itemof interest is being detected by the describe system. While passingthrough the sample 108, the output signal 106 has a unique OAM signatureapplied thereto that is provided as an OAM distinct signature signal110. OAM beams have been observed to exhibit unique topologicalevolution upon interacting with chiral solutions. While it has been seenthat chiral molecules create unique OAM signatures when an OAM beam ispassed through a sample of the chiral material, the generation of uniqueOAM signatures from signals passing through non-chiralmolecules/material may also be provided. Given these unique topologicalfeatures one can detect the existence of a molecule in a given solutionwith specific signatures in both the amplitude and phase measurements.This distinct signature signal 110 may then be examined using forexample a camera 112 in order to detect the unique signalcharacteristics applied thereto and determine the material within thesample based upon this unique signature. Detection of differentmolecules can be applied to different industries including, but notlimited to, food, chemicals, pharma and medical testings wherenon-invasive solutions are critical. The determination of the particularmaterial indicated by the unique signature may be determined in oneembodiment by comparison of the signature to a unique database ofsignatures that include known signatures that are associated with aparticular material or concentration. The manner of creating such adatabase would be known to one skilled in the art.

Referring now to FIG. 2 illustrates the manner in which an OAM generator220 may generate an OAM twisted beam 222. The OAM generator 210 may useany number of devices to generate the twisted beam 222 includingholograms with an amplitude mask, holograms with a phase mask, SpatialLight Modulators (SLMs) or Digital Light Processors (DLPs). The OAMgenerator 220 receives a light beam 221 (for example from a laser) thatincludes a series of plane waves. The OAM generator 220 applies anorbital angular momentum to the beam 222. The beam 222 includes a singleOAM mode as illustrated by the intensity diagram 223. The OAM twistedbeam 222 is passed through a sample 224 including material that is beingdetected. As mentioned previously the sample 224 may be in a containeror its naturally occurring location. The presence of the material withinthe sample 224 will create new OAM mode levels within the intensitydiagram 225. Once the beam 222 passes through the sample 224, the outputbeam 226 will have three distinct signatures associated therewith basedon a detection of a particular material at a particular concentration.These signatures include a change in eccentricity 228 of the intensitypattern, a shift or translation 230 in the center of gravity of theintensity pattern and a rotation 232 in three general directions (α, β,γ) of the ellipsoidal intensity pattern output. Each of these distinctsignature indications may occur in any configuration and each distinctsignature will provide a unique indication of the presence of particularmaterials and the concentrations of these detected materials. Thesethree distinct signatures will appear when a molecule under measurementis detected and the manner of change of these signatures representsconcentration levels. The detection of the helicity spectrums from thebeam passing through the sample 224 involves detecting the helical wavescatters (forward and backward) from the sample material.

The use of the OAM of light for the metrology of glucose, amyloid betaand other chiral materials has been demonstrated using theabove-described configurations. OAM beams are observed to exhibit uniquetopological evolution upon interacting with chiral solutions within 3 cmoptical path links. It should be realized that unique topologicalevolution may also be provided from non-chiral materials. Chiralsolution, such as Amyloid-beta, glucose and others, have been observedto cause orbital angular momentum (OAM) beams to exhibit uniquetopological evolution when interacting therewith. OAM is not typicallycarried by naturally scattered photons which make use of the twistedbeams more accurate when identifying the helicities of chiral moleculesbecause OAM does not have ambient light scattering (noise) in itsdetection. Thus, the unique OAM signatures imparted by a material is notinterfered with by ambient light scattering (noise) that does not carryOAM in naturally scattered photons making detection much more accurate.Given these unique topological features one can detect the amyloid-betapresence and concentration within a given sample based upon a specificsignature in both amplitude and phase measurements. Molecular chiralitysignifies a structural handedness associated with variance under spatialinversion or a combination of inversion and rotation, equivalent to theusual criteria of a lack of any proper axes of rotation. Something ischiral when something cannot be made identical to its reflection. Chiralmolecules that are not superimposable on their mirror image are known asEnantiomers. Traditionally, chiral optics engages circularly polarizedlight, even in the case of optical rotation, interpretation of thephenomenon commonly requires the plane polarized state to be understoodas a superposition of circular polarizations with opposite handedness.For circularly polarized light, the left and right forms designate thesign of intrinsic spin angular momentum, ±h and also the helicity of thelocus described by the associated electromagnetic field vectors. Forthis reason its interactions with matter are enantiomerically specific.

The continuous symmetry measure (CSM) is used to evaluate the degree ofsymmetry of a molecule, or the chirality. This value ranges from 0 to100. The higher the symmetry value of a molecule the more symmetrydistorted the molecule and the more chiral the molecule. The measurementis based on the minimal distance between the chiral molecule and thenearest achiral molecule.

The continuous symmetry measure may be achieved according to theequation:

${S(G)} = {100 \times \min\frac{1}{{Nd}^{2}}{\sum\limits_{k = 1}^{N}{{Q_{k} - {\hat{Q}}_{k}}}^{2}}}$Q_(k): The original structure{circumflex over (Q)}_(k): The symmetry-operated structureN: Number of verticesd: Size normalization factor*The scale is 0-1 (0-100):The larger S(G) is, the higher is the deviation from G-symmetry

SG as a continuous chirality measure may be determined according to:

${S(G)} = {100 \times \min\frac{1}{{Nd}^{2}}{\sum\limits_{k = 1}^{N}{{Q_{k} - {\hat{Q}}_{k}}}^{2}}}$G: The achiral symmetry point group which minimizes S(G)Achiral molecule: S(G)=0

An achiral molecule has a value of S(G)=0. The more chiral a molecule isthe higher the value of S(G).

The considerable interest in orbital angular momentum has been enhancedthrough realization of the possibility to engineer optical vortices.Here, helicity is present in the wavefront surface of theelectromagnetic fields and the associated angular momentum is termed“orbital”. The radiation itself is commonly referred to as a ‘twisted’or ‘helical’ beam. Mostly, optical vortices have been studied only intheir interactions with achiral matter—the only apparent exception issome recent work on liquid crystals. It is timely and of interest toassess what new features, if any, can be expected if such beams are usedto interrogate any system whose optical response is associated withenantiomerically specific molecules.

First the criteria for manifestations of chirality in opticalinteractions are constructed in generalized form. For simplicity,materials with a unique enantiomeric specificity are assumed—signifyinga chirality that is intrinsic and common to all molecular components (orchromophores) involved in the optical response. Results for systems ofthis kind will also apply to single molecule studies. Longer rangetranslation/rotation order can also produce chirality, as for example intwisted nematic crystals, but such mesoscopic chirality cannot directlyengender enantiomerically specific interactions. The only exception iswhere optical waves probe two or more electronically distinct,dissymmetrically oriented but intrinsically achiral molecules orchromophores.

Chiroptical interactions can be distinguished by their electromagneticorigins: for molecular systems in their usual singlet electronic groundstate, they involve the spatial variation of the electric and magneticfields associated with the input of optical radiation. This variationover space can be understood to engage chirality either through itscoupling with di-symmetrically placed, neighboring chromophore groups(Kirkwood's two-group model, of limited application) or more generallythrough the coupling of its associated electric and magnetic fields withindividual groups. As chirality signifies a local breaking of parity itpermits an interference of electric and magnetic interactions. Even inthe two group case, the paired electric interactions of the systemcorrespond to electric and magnetic interactions of the single entitywhich the two groups comprise. Thus, for convenience, the term ‘chiralcenter’ is used in the following to denote either chromophore ormolecule.

With the advent of the laser, the Gaussian beam solution to the waveequation came into common engineering parlance, and its extension twohigher order laser modes, Hermite Gaussian for Cartesian symmetry;Laguerre Gaussian for cylindrical symmetry, etc., entered laboratoryoptics operations. Higher order Laguerre Gaussian beam modes exhibitspiral, or helical phase fronts. Thus, the propagation vector, or theeikonal of the beam, and hence the beams momentum, includes in additionto a spin angular momentum, an orbital angular momentum, i.e. a wobblearound the sea axis. This phenomenon is often referred to as vorticity.The expression for a Laguerre Gaussian beam is given in cylindricalcoordinates:

${u\left( {r,\theta,z} \right)} = {\sqrt{\frac{2{pl}}{1 + {\delta_{0,m}{{\pi\left( {m + p} \right)}!}}}}\frac{1}{w(z)}{\exp\left\lbrack {{j\left( {{2p} + m + 1} \right)}\left( {{\psi(z)} - \psi_{0}} \right)} \right\rbrack}\left( \frac{\sqrt{2}r}{w(z)} \right){L_{p}^{m}\left( \frac{2r^{2}}{{w(z)}^{2}} \right)}{\exp\left\lbrack {{{- j}\; k\frac{r^{2}}{2{q(z)}}} + {i\; m\;\theta}} \right\rbrack}}$

Here, w(x) is the beam spot size, q(c) is the complex beam parametercomprising the evolution of the spherical wave front and the spot size.Integers p and m are the radial and azimuthal modes, respectively. Theexp(imθ) term describes the spiral phase fronts.

Referring now also to FIG. 3, there is illustrated one embodiment of abeam for use with the system. A light beam 300 consists of a stream ofphotons 302 within the light beam 300. Each photon has an energy ±hω anda linear momentum of ±hk which is directed along the light beam axis 304perpendicular to the wavefront. Independent of the frequency, eachphoton 302 within the light beam has a spin angular momentum 306 of ±haligned parallel or antiparallel to the direction of light beampropagation. Alignment of all of the photons 302 spins gives rise to acircularly polarized light beam. In addition to the circularpolarization, the light beams also may carry an orbital angular momentum308 which does not depend on the circular polarization and thus is notrelated to photon spin.

Lasers are widely used in optical experiments as the source ofwell-behaved light beams of a defined frequency. A laser may be used forproviding the light beam 300. The energy flux in any light beam 300 isgiven by the Poynting vector which may be calculated from the vectorproduct of the electric and magnetic fields within the light beam. In avacuum or any isotropic material, the Poynting vector is parallel to thewave vector and perpendicular to the wavefront of the light beam. In anormal laser light, the wavefronts 400 are parallel as illustrated inFIG. 4. The wave vector and linear momentum of the photons are directedalong the axis in a z direction 402. The field distributions of suchlight beams are paraxial solutions to Maxwell's wave equation butalthough these simple beams are the most common, other possibilitiesexist.

For example, beams that have l intertwined helical fronts are alsosolutions of the wave equation. The structure of these complicated beamsis difficult to visualize, but their form is familiar from the l=3fusilli pasta. Most importantly, the wavefront has a Poynting vector anda wave vector that spirals around the light beam axis direction ofpropagation as illustrated in FIG. 5 at 502.

A Poynting vector has an azimuthal component on the wave front and anon-zero resultant when integrated over the beam cross-section. The spinangular momentum of circularly polarized light may be interpreted in asimilar way. A beam with a circularly polarized planer wave front, eventhough it has no orbital angular momentum, has an azimuthal component ofthe Poynting vector proportional to the radial intensity gradient. Thisintegrates over the cross-section of the light beam to a finite value.When the beam is linearly polarized, there is no azimuthal component tothe Poynting vector and thus no spin angular momentum.

Thus, the momentum of each photon 302 within the light beam 300 has anazimuthal component. A detailed calculation of the momentum involves allof the electric fields and magnetic fields within the light beam,particularly those electric and magnetic fields in the direction ofpropagation of the beam. For points within the beam, the ratio betweenthe azimuthal components and the z components of the momentum is foundto be l/kr. (where l=the helicity or orbital angular momentum; k=wavenumber 2π/λ; r=the radius vector.) The linear momentum of each photon302 within the light beam 300 is given by hk, so if we take the crossproduct of the azimuthal component within a radius vector, r, we obtainan orbital momentum for a photon 602 of lh. Note also that the azimuthalcomponent of the wave vectors is l/r and independent of the wavelength.

Referring now to FIGS. 6 and 7, there are illustrated plane wavefrontsand helical wavefronts. Ordinarily, laser beams with plane wavefronts602 are characterized in terms of Hermite-Gaussian modes. These modeshave a rectangular symmetry and are described by two mode indices m 604and n 606. There are m nodes in the x direction and n nodes in the ydirection. Together, the combined modes in the x and y direction arelabeled HG_(mn) 608. In contrast, as shown in FIG. 7, beams with helicalwavefronts 702 are best characterized in terms of Laguerre-Gaussianmodes which are described by indices I 703, the number of intertwinedhelices 704, and p, the number of radial nodes 706. TheLaguerre-Gaussian modes are labeled LG_(mn) 710. For l≠0, the phasesingularity on a light beam 300 results in 0 on axis intensity. When alight beam 300 with a helical wavefront is also circularly polarized,the angular momentum has orbital and spin components, and the totalangular momentum of the light beam is (l±h) per photon.

Using the orbital angular momentum state of the transmitted energysignals, physical information can be embedded within the electromagneticradiation transmitted by the signals. The Maxwell-Heaviside equationscan be represented as:

${\nabla{\cdot E}} = \frac{\rho}{ɛ_{0}}$${\nabla{\times E}} = {- \frac{\partial B}{\partial t}}$ ∇⋅B = 0${\nabla{\times B}} = {{ɛ_{0}\mu_{0}\frac{\partial E}{\partial t}} + {\mu_{0}{j\left( {t,x} \right)}\mspace{14mu}{the}}}$where ∇ is the del operator, E is the electric field intensity and B isthe magnetic flux density. Using these equations, we can derive 23symmetries/conserve quantities from Maxwell's original equations.However, there are only ten well-known conserve quantities and only afew of these are commercially used. Historically if Maxwell's equationswhere kept in their original quaternion forms, it would have been easierto see the symmetries/conserved quantities, but when they were modifiedto their present vectorial form by Heaviside, it became more difficultto see such inherent symmetries in Maxwell's equations.

The conserved quantities and the electromagnetic field can berepresented according to the conservation of system energy and theconservation of system linear momentum. Time symmetry, i.e. theconservation of system energy can be represented using Poynting'stheorem according to the equations:

$H = {{\sum\limits_{i}{m_{i}\gamma_{i}c^{2}}} + {\frac{ɛ_{0}}{2}{\int{d^{3}{x\left( {{E}^{2} + {c^{2}{B}^{2}}} \right)}}}}}$${\frac{{dU}^{mech}}{dt} + \frac{{dU}^{em}}{dt} + {\oint_{s^{\prime}}{d^{2}x^{\prime}{\hat{n^{\prime}} \cdot S}}}} = 0$

The space symmetry, i.e., the conservation of system linear momentumrepresenting the electromagnetic Doppler shift can be represented by theequations:

$P = {{\sum\limits_{i}{m_{i}\gamma_{i}v_{i}}} + {ɛ_{0}{\int{d^{3}{x\left( {E \times B} \right)}}}}}$${\frac{{dp}^{mech}}{dt} + \frac{{dp}^{em}}{dt} + {\oint_{s^{\prime}}{d^{2}x^{\prime}{\hat{n^{\prime}} \cdot T}}}} = 0$

The conservation of system center of energy is represented by theequation:

$R = {{\frac{1}{H}{\sum\limits_{i}\;{\left( {x_{i} - x_{0}} \right)m_{i}\gamma_{i}c^{2}}}} + {\frac{ɛ_{0}}{2H}{\int{d^{3}{x\left( {x - x_{0}} \right)}\left( {{E^{2}} + {c^{2}{B^{2}}}} \right)}}}}$

Similarly, the conservation of system angular momentum, which gives riseto the azimuthal Doppler shift is represented by the equation:

${\frac{{dJ}^{mech}}{dt} + \frac{{dJ}^{em}}{dt} + {\oint_{s^{\prime}}{d^{2}x^{\prime}{\hat{n^{\prime}} \cdot M}}}} = 0$

For radiation beams in free space, the EM field angular momentum J^(em)can be separated into two parts:J ^(em)=ε₀∫_(V′) d ³ x′(E×A)+ε₀∫_(V′) d ³ x′E _(i)[(x′−x ₀)×∇]A _(i)

For each singular Fourier mode in real valued representation:

$J^{em} = {{{- i}\frac{ɛ_{0}}{2\omega}{\int_{V^{\prime}}\ {d^{3}{x^{\prime}\left( {E^{*} \times E} \right)}}}} - {i\frac{ɛ_{0}}{2\omega}{\int_{V^{\prime}}\ {d^{3}x^{\prime}{E_{i}\left\lbrack {\left( {x^{\prime} - x_{0}} \right) \times \nabla} \right\rbrack}E_{i}}}}}$

The first part is the EM spin angular momentum S^(em), its classicalmanifestation is wave polarization. And the second part is the EMorbital angular momentum L^(em) its classical manifestation is wavehelicity. In general, both EM linear momentum P^(em), and EM angularmomentum J^(em)=L^(em)+S^(em) are radiated all the way to the far field.

By using Poynting theorem, the optical vorticity of the signals may bedetermined according to the optical velocity equation:

${\frac{\partial U}{\partial t} + {\nabla{\cdot S}}} = 0$where S is the Poynting vector

$S = {\frac{1}{4}\left( {{E \times H^{*}} + {E^{*} \times H}} \right)}$and U is the energy density

$U = {\frac{1}{4}\left( {{ɛ{E}^{2}} + {\mu_{0}{H}^{2}}} \right)}$with E and H comprising the electric field and the magnetic field,respectively, and ε and μ₀ being the permittivity and the permeabilityof the medium, respectively. The optical vorticity V may then bedetermined by the curl of the optical velocity according to theequation:

$V = {{\nabla{\times v_{opt}}} = {\nabla{\times \left( \frac{{E \times H^{*}} + {E^{*} \times H}}{{ɛ{E}^{2}} + {\mu_{0}{H}^{2}}} \right)}}}$

Referring now to FIGS. 8 and 9, there are illustrated the manner inwhich a signal and an associated Poynting vector of the signal vary in aplane wave situation (FIG. 8) where only the spin vector is altered, andin a situation wherein the spin and orbital vectors are altered in amanner to cause the Poynting vector to spiral about the direction ofpropagation (FIG. 9).

In the plane wave situation, illustrated in FIG. 8, when only the spinvector of the plane wave is altered, the transmitted signal may take onone of three configurations. When the spin vectors are in the samedirection, a linear signal is provided as illustrated generally at 804.It should be noted that while 804 illustrates the spin vectors beingaltered only in the x direction to provide a linear signal, the spinvectors can also be altered in the y direction to provide a linearsignal that appears similar to that illustrated at 804 but in aperpendicular orientation to the signal illustrated at 804. In linearpolarization such as that illustrated at 804, the vectors for the signalare in the same direction and have a same magnitude.

Within a circular polarization as illustrated at 806, the signal vectors812 are 90 degrees to each other but have the same magnitude. Thiscauses the signal to propagate as illustrated at 806 and provide thecircular polarization 814 illustrated in FIG. 8. Within an ellipticalpolarization 808, the signal vectors 816 are also 90 degrees to eachother but have differing magnitudes. This provides the ellipticalpolarizations 818 illustrated for the signal propagation 408. For theplane waves illustrated in FIG. 8, the Poynting vector is maintained ina constant direction for the various signal configurations illustratedtherein.

The situation in FIG. 9 illustrates when a unique orbital angularmomentum is applied to a signal. When this occurs, Poynting vector S 910will spiral around the general direction of propagation 912 of thesignal. The Poynting vector 910 has three axial components S_(φ), S_(p)and S_(z) which vary causing the vector to spiral about the direction ofpropagation 912 of the signal. The changing values of the variousvectors comprising the Poynting vector 910 may cause the spiral of thePoynting vector to be varied in order to enable signals to betransmitted on a same wavelength or frequency as will be more fullydescribed herein. Additionally, the values of the orbital angularmomentum indicated by the Poynting vector 910 may be measured todetermine the presence of particular materials and the concentrationsassociated with particular materials being processed by a scanningmechanism.

FIGS. 10A-10C illustrate the differences in signals having a differenthelicity (i.e., orbital angular momentum applied thereto). The differinghelicities would be indicative of differing materials and concentrationof materials within a sample that a beam was being passed through. Bydetermining the particular orbital angular momentum signature associatedwith a signal, the particular material and concentration amounts of thematerial could be determined. Each of the spiraling Poynting vectorsassociated with a signal 1002, 1004 and 1006 provides a different-shapedsignal. Signal 1002 has an orbital angular momentum of +1, signal 1004has an orbital angular momentum of +3 and signal 1006 has an orbitalangular momentum of −4. Each signal has a distinct orbital angularmomentum and associated Poynting vector enabling the signal to beindicative of a particular material and concentration of material thatis associated with the detected orbital angular momentum. This allowsdeterminations of materials and concentrations of various types ofmaterials to be determined from a signal since the orbital angularmomentums are separately detectable and provide a unique indication ofthe particular material and the concentration of the particular materialthat has affected the orbital angular momentum of the signal transmittedthrough the sample material.

FIG. 11 illustrates the propagation of Poynting vectors for variousEigen modes. Each of the rings 1120 represents a different Eigen mode ortwist representing a different orbital angular momentum. Each of thedifferent orbital angular momentums is associated with particularmaterial and a particular concentration of the particular material.Detection of orbital angular momentums provides an indication of the apresence of an associated material and a concentration of the materialthat is being detected by the apparatus. Each of the rings 1120represents a different material and/or concentration of a selectedmaterial that is being monitored. Each of the Eigen modes has a Poyntingvector 1122 for generating the rings indicating different materials andmaterial concentrations.

Referring now to FIG. 12, there is illustrated a block diagram of theapparatus for providing detection of the presence of a material andconcentration measurements of various materials responsive to theorbital angular momentum detected by the apparatus in accordance withthe principles described herein above. An emitter 1202 transmits waveenergy 1204 that comprises a series of plane waves. The emitter 1202 mayprovide a series of plane waves such as those describes previously withrespect to FIG. 7. The orbital angular momentum generation circuitry1206 generates a series of waves having an orbital angular momentumapplied to the waves 1208 in a known manner. The orbital angularmomentum generation circuitry 1206 may utilize holograms or some othertype of orbital angular momentum generation process as will be morefully described herein below. The OAM generation circuitry 1206 may begenerated by transmitting plane waves through a spatial light modulator(SLM), an amplitude mask or a phase mask. The orbital angular momentumtwisted waves 1208 are applied to a sample material 1210 under test. Thesample material 1210 contains a material, and the presence andconcentration of the material is determined via a detection apparatus inaccordance with the process described herein. The sample material 1210may be located in a container or at its naturally occurring location innature such as an individual's body.

A series of output waves 1212 from the sample material 1210 exit thesample and have a particular orbital angular momentum imparted theretoas a result of the material and the concentration of the particularmaterial under study within the sample material 1210. The output waves1212 are applied to a matching module 1214 that includes a mappingaperture for amplifying a particular orbital angular momentum generatedby the specific material under study. The matching module 1214 willamplify the orbital angular momentums associated with the particularmaterial and concentration of material that is detected by theapparatus. The amplified OAM waves 1216 are provided to a detector 1218.The detector 1218 detects OAM waves relating to the material and theconcentration of a material within the sample and provides thisinformation to a user interface 1220. The detector 1218 may utilize acamera to detect distinct topological features from the beam passingthrough the sample. The user interface 1220 interprets the informationand provides relevant material type and concentration indication to anindividual or a recording device.

Referring now to FIG. 13, there is more particularly illustrated theemitter 1202. The emitter 1202 may emit a number of types of energywaves 1204 to the OAM generation module 1206. The emitter 1202 may emitoptical waves 1300, electromagnetic waves 1302, acoustic waves 1304 orany other type of particle waves 1306. The emitted waves 1204 are planewaves such as those illustrated in FIG. 4 having no orbital angularmomentum applied thereto and may come from a variety of types ofemission devices and have information included therein. In oneembodiment, the emission device may comprise a laser. Plane waves havewavefronts that are parallel to each other having no twist or helicityapplied thereto, and the orbital angular momentum of the wave is equalto 0. The Poynting vector within a plane wave is completely in line withthe direction of propagation of the wave.

The OAM generation module 1206 processes the incoming plane wave 1204and imparts a known orbital angular momentum onto the plane waves 1204provided from the emitter 1202. The OAM generation module 1206 generatestwisted or helical electromagnetic, optic, acoustic or other types ofparticle waves from the plane waves of the emitter 1202. A helical wave1208 is not aligned with the direction of propagation of the wave buthas a procession around direction of propagation as shown in FIG. 14.The OAM generation module 1206 may comprise in one embodiment a fixedorbital angular momentum generator 1402 as illustrated in FIG. 14. Thefixed orbital angular momentum generator 1402 receives the plane waves1204 from the emitter 1202 and generates an output wave 1404 having afixed orbital angular momentum applied thereto.

The fixed orbital angular momentum generator 1402 may in one embodimentcomprise a holographic image for applying the fixed orbital angularmomentum to the plane wave 1204 in order to generate the OAM twistedwave 1404. Various types of holographic images may be generated in orderto create the desired orbital angular momentum twist to an opticalsignal that is being applied to the orbital angular momentum generator1402. Various examples of these holographic images are illustrated inFIG. 15A-15D. In one embodiment, the conversion of the plane wavesignals transmitted from the emitter 1202 by the orbital angularmomentum generation circuitry 1206 may be achieved using holographicimages.

Most commercial lasers emit an HG₀₀ (Hermite-Gaussian) mode 1602 (FIG.16) with a planar wave front and a transverse intensity described by aGaussian function. Although a number of different methods have been usedto successfully transform an HG₀₀ Hermite-Gaussian mode 1602 into aLaguerre-Gaussian mode 1604, the simplest to understand is the use of ahologram.

The cylindrical symmetric solution u_(pl) (r,φ,z) which describesLaguerre-Gaussian beams, is given by the equation:

${{{{u_{pl}\left( {r,\phi,z} \right)} = {{\frac{C}{\left( {1 + \frac{z^{2}}{z_{R}^{2}}} \right)^{\frac{1}{2}}}\left\lbrack \frac{r\sqrt{2}}{w(z)} \right\rbrack}^{l}{L_{p}^{l}\left\lbrack \frac{2r^{2}}{w^{2}(z)} \right\rbrack}{\exp\left\lbrack \frac{- r^{2}}{w^{2}(z)} \right\rbrack}{\exp\left\lbrack \frac{{- {ikr}^{2}}z}{2\left( {z^{2} + z_{R}^{2}} \right)} \right\rbrack}{\exp\left( {{- {il}}\phi} \right)}}}\quad}\quad}{\quad{\times {\quad\quad}{\exp\left\lbrack {{i\left( {{2p} + l + 1} \right)}\tan^{- 1}\frac{z}{z_{R}}} \right\rbrack}}}$Where z_(R) is the Rayleigh range, w(z) is the radius of the beam, L_(P)is the Laguerre polynomial, C is a constant, and the beam waist is atz=0.

In its simplest form, a computer generated hologram is produced from thecalculated interference pattern that results when the desired beamintersects the beam of a conventional laser at a small angle. Thecalculated pattern is transferred to a high resolution holographic film.When the developed hologram is placed in the original laser beam, adiffraction pattern results. The first order of which has a desiredamplitude and phase distribution. This is one manner for implementingthe OAM generation module 1206. A number of examples of holographicimages for use within a OAM generation module are illustrated withrespect to FIGS. 15A-15D.

There are various levels of sophistication in hologram design. Hologramsthat comprise only black and white areas with no grayscale are referredto as binary holograms. Within binary holograms, the relativeintensities of the two interfering beams play no role and thetransmission of the hologram is set to be zero for a calculated phasedifference between zero and π, or unity for a phase difference between πand 2π. A limitation of binary holograms is that very little of theincident power ends up in the first order diffracted spot, although thiscan be partly overcome by blazing the grating. When mode purity is ofparticular importance, it is also possible to create more sophisticatedholograms where the contrast of the pattern is varied as a function ofradius such that the diffracted beam has the required radial profile.

A plane wave shining through the holographic images 1502 will have apredetermined orbital angular momentum shift applied thereto afterpassing through the holographic image 1502. OAM generator 1202 is fixedin the sense that a same image is used and applied to the beam beingpassed through the holographic image. Since the holographic image 1502does not change, the same orbital angular momentum is always applied tothe beam being passed through the holographic image 1502. While FIGS.15A-15D illustrate a number of embodiments of various holographic imagesthat might be utilized within the orbital angular momentum generator1202, it will be realized that any type of holographic image 1502 may beutilized in order to achieve the desired orbital angular momentum withinan beam being shined through the image 1502.

In another example of a holographic image illustrated in FIG. 17, thereis illustrated a hologram that utilizes two separate holograms that aregridded together to produce a rich number of orbital angular momentum(l). The superimposed holograms of FIG. 17 have an orbital angularmomentum of l=1 and l=3 which are superimposed upon each other tocompose the composite vortex grid 1702. The holograms utilized may alsobe built in a manner that the two holograms are gridded together toproduce a varied number of orbital angular momentums (l) not just on aline (l=+1, l=0, l=−1) but on a square which is able to identify themany variables more easily. Thus, in the example in FIG. 17, the orbitalangular momentums along the top edge vary from +4 to +1 to −2 and on thebottom edge from +2 to −1 to −4. Similarly, along the left edge theorbital angular momentums vary from +4 to +3 to +2 and on the right edgefrom −2 to −3 to −4. Across the horizontal center of the hologram theorbital angular momentums provided vary from +3 to 0 to −3 and along thevertical axis vary from +1 to 0 to −1. Thus, depending upon the portionof the grid a beam may pass through, varying orbital angular momentummay be achieved.

Referring now to FIG. 18, in addition to a fixed orbital angularmomentum generator, the orbital angular momentum generation circuitry1206 may also comprise a tunable orbital angular momentum generatorcircuitry 1802. The tunable orbital angular momentum generator 1802receives the input plane wave 1204 but additionally receives one or moretuning parameters 1804. The tuning parameters 1804 tune the tunable OAMgenerator 1802 to apply a selected orbital angular momentum so that thetuned OAM wave 1806 that is output from the OAM generator 1802 has aselected orbital angular momentum value applied thereto.

This may be achieved in any number of fashions. In one embodiment,illustrated in FIG. 22, the tunable orbital angular momentum generator1802 may include multiple hologram images 2202 within the tunable OAMgenerator 1802. The tuning parameters 1804 enable selection of one ofthe holographic images 2206 in order to provide the desired OAM wavetwisted output signal 1806 through a selector circuit 2204.Alternatively, the gridded holographic image such as that described inFIG. 16 may be utilized and the beam shined on a portion of the griddedimage to provide the desired OAM output. The tunable OAM generator 1802has the advantage of being controlled to apply a particular orbitalangular momentum to the output orbital angular momentum wave 1806depending upon the provided input parameter 1804. This enables thepresence and concentrations of a variety of different materials to bemonitored, or alternatively, for various different concentrations of thesame material to be monitored.

Referring now to FIG. 19, there is more particularly implemented a blockdiagram of a tunable orbital angular momentum generator 1802. Thegenerator 1802 includes a plurality of holographic images 1902 forproviding orbital angular momentums of various types to a provided lightsignal. These holographic images 1902 are selected responsive to aselector circuitry 1904 that is responsive to the input tuningparameters 1804. The selected filter 1906 comprises the holographicimage that has been selected responsive to the selector controller 1904and receives the input plane waves 1204 to provide the tuned orbitalangular momentum wave output 1206. In this manner, signals having adesired orbital angular momentum may be output from the OAM generationcircuitry 1206.

Referring now to FIG. 20, there is illustrated the manner in which theoutput of the OAM generator 1206 may vary a signal by applying differentorbital angular momentums thereto. FIG. 20 illustrates helical phasefronts in which the Poynting vector is no longer parallel to the beamaxis and thus has an orbital angular momentum applied thereto. In anyfixed radius within the beam, the Poynting vector follows a spiraltrajectory around the axis. Rows are labeled by 1, the orbital angularmomentum quantum number, L=lh is the beams orbital angular momentum perphoton within the output signal. For each l, the left column 2002 is thelight beam's instantaneous phase. The center column 2004 comprises theangular intensity profiles and the right column 2006 illustrates whatoccurs when such a beam interferes with a plane wave and produces aspiral intensity pattern. This is illustrated for orbital angularmomentums of −1, 0, 1, 2 and 3 within the various rows of FIG. 23.

Referring now to FIG. 21, there is illustrated an alternative manner inwhich the OAM generator 1206 may convert a Hermite-Gaussian beam outputfrom an emitter 1202 to a Laguerre-Gaussian beams having impartedtherein an orbital angular momentum using mode converters 2104 and aDove prism 2110. The Hermite-Gaussian mode plane waves 2102 are providedto a π/2 mode convertor 2104. The π/2 mode convertor 2104 produce beamsin the Laguerre-Gaussian modes 2106. The Laguerre-Gaussian modes beams2106 are applied to either a π mode convertor 2108 or a dove prism 2110that reverses the mode to create a reverse Laguerre-Gaussian mode signal2112.

Referring now to FIG. 22, there is illustrated the manner in whichholograms within the OAM generator 1206 generate a twisted light beam. Ahologram 2202 can produce light beam 2204 and light beam 2206 havinghelical wave fronts and associated orbital angular momentum lh perphoton. The appropriate hologram 2202 can be calculated or generatedfrom the interference pattern between the desired beam form 2204, 2206and a plane wave 2208. The resulting holographic pattern within thehologram 2202 resembles a diffraction grating, but has a 1-prongeddislocation at the beam axis. When the hologram is illuminated with theplane wave 2208, the first-order diffracted beams 2204 and 2206 have thedesired helical wave fronts to provide the desired first ordereddiffracted beam display 2210.

Referring now to FIG. 23, there is more particularly illustrated themanner in which the sample 1210 receives the input OAM twisted wave 1208provided from the OAM generator 1206 and provides an output OAM wave1212 having a particular OAM signature associated therewith that dependsupon the material or the concentration of a particular monitoredmaterial within the sample 1210. The sample 1210 may comprise any samplethat is under study and may be in a solid form, liquid form or gas form.The sample material 1210 that may be detected using the system describedherein may comprise a variety of different materials. As statedpreviously, the material may comprise liquids such as blood, water, oilor chemicals. The various types of carbon bondings such as C—H, C—O,C—P, C—S or C—N may be provided for detection. The system may alsodetect various types of bondings between carbon atoms such as a singlebond (methane or Isooctane), dual bond items (butadiene and benzene) ortriple bond carbon items such as acetylene.

The sample 1210 may include detectable items such as organic compoundsincluding carbohydrates, lipids (cylcerol and fatty acids), nucleicacids (C, H, O, N, P) (RNA and DNA) or various types of proteins such aspolyour of amino NH₂ and carboxyl COOH or aminos such as tryptophan,tyrosine and phenylalanine. Various chains within the samples 1210 mayalso be detected such as monomers, isomers and polymers. Enzymes such asATP and ADP within the samples may be detected. Substances produced orreleased by glands of the body may be in the sample and detected. Theseinclude items released by the exocrine glands via tube/ducts, endocrineglands released directly into blood samples or hormones. Various typesof glands that may have their secretions detected within a sample 1210include the hypothalamus, pineal and pituitary glands, the parathyroidand thyroid and thymus, the adrenal and pancreas glands of the torso andthe hormones released by the ovaries or testes of a male or female.

The sample 1210 may also be used for detecting various types ofbiochemical markers within the blood and urine of an individual such asmelanocytes and keratinocytes. The sample 1210 may include various partsof the body to detect defense substances therein. For example, withrespect to the skin, the sample 1210 may be used to detect carotenoids,vitamins, enzymes, b-carotene and lycopene. With respect to the eyepigment, the melanin/eumelanin, dihydroxyindole or carboxylic may bedetected. The system may also detect various types of materials withinthe body's biosynthetic pathways within the sample 1210 includinghemoglobin, myoglobin, cytochromes, and porphyrin molecules such asprotoporphyrin, coporphyrin, uroporphyrin and nematoporphyrin. Thesample 1210 may also contain various bacterial to be detected such aspropion bacterium, acnes. Also various types of dental plaque bacteriamay be detected such as porphyromonos gingivitis, prevotella intremediand prevotella nigrescens. The sample 1210 may also be used for thedetection of glucose in insulin within a blood sample 1210. The sample1210 may also include amyloid-beta detection. Detection of amyloid-betawithin the sample may then be used for determinations of early onsetAlzheimer's. Higher levels of amyloid-beta may provide an indication ofthe early stages of Alzheimer's. The sample 1210 may comprise anymaterial that is desired to be detected that provides a unique OAM twistto a signal passing through the sample.

The orbital angular momentum within the beams provided within the sample1210 may be transferred from light to matter molecules depending uponthe rotation of the matter molecules. When a circularly polarized laserbeam with a helical wave front traps a molecule in an angular ring oflight around the beam axis, one can observe the transfer of both orbitaland spin angular momentum. The trapping is a form of optical tweezingaccomplished without mechanical constraints by the ring's intensitygradient. The orbital angular momentum transferred to the molecule makesit orbit around the beam axis as illustrated at 2402 of FIG. 24. Thespin angular momentum sets the molecule spinning on its own axis asillustrated at 2404.

The output OAM wave 1212 from the sample 1210 will have an orbitalangular momentum associated therewith that is different from the orbitalangular momentum provided on the input OAM wave 1208. The difference inthe output OAM wave 1212 will depend upon the material contained withinthe sample 1210 and the concentration of these materials within thesample 1210. Differing materials of differing concentration will haveunique orbital angular momentums associated therewith. Thus, byanalyzing the particular orbital angular momentum signature associatedwith the output OAM wave 1212, determinations may be made as to thematerials present within the sample 1210 and the concentration of thesematerials within the sample may also be determined.

Referring now to FIG. 25, the matching module 1214 receives the outputorbital angular momentum wave 1212 from the sample 1210 that has aparticular signature associated therewith based upon the orbital angularmomentum imparted to the waves passing through the sample 1210. Thematching module 1214 amplifies the particular orbital angular momentumof interest in order to provide an amplified wave having the desiredorbital angular momentum of interest 1216 amplified. The matching module1214 may comprise a matching aperture that amplifies the detectionorbital angular momentum associated with a specific material orcharacteristic that is under study. The matching module 1214 may in oneembodiment comprise a holographic filter such as that described withrespect to FIGS. 15A-15D in order to amplify the desired orbital angularmomentum wave of interest. The matching module 1214 is established basedupon a specific material of interest that is trying to be detected bythe system. The matching module 1214 may comprise a fixed module usingholograms as illustrated in FIGS. 15A-15D or a tunable module in amanner similar to that discussed with respect to the OAM generationmodule 1206. In this case, a number of different orbital angularmomentums could be amplified by the matching module in order to detectdiffering materials or differing concentrations of materials within thesample 1210. Other examples of components for the matching module 1214include the use of quantum dots, nanomaterials or metamaterials in orderto amplify any desired orbital angular momentum values within a receivedwave form from the sample 1210.

Referring now to FIG. 26, the matching module 1214 rather than usingholographic images in order to amplify the desired orbital angularmomentum signals may use non-linear crystals in order to generate higherorbital angular momentum light beams. Using a non-linear crystal 2602, afirst harmonic orbital angular momentum beam 2604 may be applied to anon-linear crystal 2602. The non-linear crystal 2602 will create asecond order harmonic signal 2606.

Referring now to FIG. 27, there is more particularly illustrated thedetector 1218 to which the amplified orbital angular momentum wave 1216from the matching circuit 1214 in order that the detector 1218 mayextract desired OAM measurements 2602. The detector 1218 receives theamplified OAM waves 1216 and detects and measures observable changeswithin the orbital angular momentum of the emitted waves due to thepresence of a particular material and the concentration of a particularmaterial under study within the sample 1210. The detector 1218 is ableto measure observable changes within the emitted amplified OAM wave 1216from the state of the input OAM wave 1208 applied to the sample 1210.The extracted OAM measurements 2702 are applied to the user interface1220. The manner in which the detector 1218 may detect differenceswithin the orbital angular momentum is more particularly illustrateswith respect to FIG. 28-30.

FIG. 28 illustrates the difference in impact between spin angularpolarization and orbital angular polarization due to passing of a beamof light through a sample 2802. In sample 2802 a, there is illustratedthe manner in which spin angular polarization is altered responsive to abeam passing through the sample 2802 a. The polarization of a wavehaving a particular spin angular momentum 2804 passing through thesample 2802 a will rotate from a position 2804 to a new position 2806.The rotation occurs within the same plane of polarization. In a similarmanner, as illustrated with respect to sample 2802 b, an image appearsas illustrated generally at 2808 before it passes through the sample2802 b. Upon passing the image through the sample 2802 b the image willrotate from the position illustrated at 2810 to a rotated positionillustrated at 2812. The amount of rotation is dependent upon thepresence of the material being detected and the level of concentrationof the material being detected within the sample 2802. Thus, as can beseen with respect to the sample 2802 of FIG. 28, both the spin angularpolarization and the orbital angular momentum will change based upon thepresence and concentration of materials within the sample 2802. Bymeasuring the amount of rotation of the image caused by the change inorbital angular momentum, the presence and concentration of a particularmaterial may be determined.

This overall process can be more particularly illustrated in FIG. 29. Alight source 2902 shines a light beam through expanding optics 2904. Theexpanded light beam is applied through a metalab generated hologram 2906that imparts an orbital angular momentum to the beam. The twisted beamfrom the hologram 2906 is shined through a sample 2908 having aparticular length L. As mentioned previously, the sample 2908 may belocated in a container or in its naturally occurring state. This causesthe generation of a twisted beam on the output side of the sample 2908to create a number of detectable waves having various orbital angularmomentums 2910 associated therewith. The image 2912 associated with thelight beam that is applied to sample 2908 will rotate an angle φdepending upon the presence and concentration of the material within thesample 2908. The rotation φ of the image 2912 is different for eachvalue orbital angular momentum −l or +l. The change in rotation of theimage Δφ may be described according to the equation:Δφ=φ₁−φ⁻¹ =f(l,L,C)Where l is orbital angular momentum number, L is the path length of thesample and C is the concentration of the material being detected.

Thus, since the length of the sample L is known and the orbital angularmomentum may be determined using the process described herein, these twopieces of information may be able to calculate a concentration of thematerial within the provided sample.

The above equation may be utilized within the user interface moreparticularly illustrated in FIG. 30. The user interface 1220 processesthe OAM measurements 3002 using an internal algorithm 3002 that providesfor the generation of material and/or concentration information 3004that may be displayed in some type of user display. The algorithm wouldin one embodiment utilize that equation described herein above in orderto determine the material and/or concentration based upon the length ofa sample and the detected variation in orbital angular momentum. Theprocess for calculating the material and/or concentration may be done ina laboratory setting where the information is transmitted wirelessly tothe lab or the user interface can be associated with a wearable deviceconnected to a meter or cell phone running an application on the cellphone connected via a local area network or wide area network to apersonal or public cloud. The user interface 3020 of the device caneither have a wired or wireless connection utilizing Bluetooth, ZigBeeor other wireless protocols.

Referring now to FIG. 31, there is illustrated the manner in which thevarious data accumulated within the user interface 1220 that has beencollected in the manner described herein above may be stored andutilized for higher level analysis. Various devices 3102 for collectingdata as described herein above may communicate via private networkclouds 3104 or with a public cloud 3106. When communicating with aprivate cloud 3104, the devices 3102 merely store information that isassociated with a particular user device that is for use with respect toanalysis of the user associated with that user device. Thus, anindividual user could be monitoring and storing information with respectto their present glucose concentrations in order to monitor and maintaintheir diabetes.

Alternatively, when information is compiled from multiple devices 3102within the public cloud 3106, this information may be provided directlyto the public cloud 3106 from the individual devices 3102 or through theprivate clouds 3104 of the associated network devices 3102. Utilizingthis information within the public cloud 3106 large databases may beestablished within servers 3108 associated with the public cloud 3106 toenable large scale analysis of various health related issues associatedwith the information processed from each of the individual devices 3102.This information may be used for analyzing public health issues.

Thus, the user interface 1220 in addition to including the algorithm3002 for determining material and/or concentration information 3004 willinclude a wireless interface 3006 enabling the collected information tobe wirelessly transmitted over the public or private cloud as describedwith respect to FIG. 31. Alternatively, the user interface may comprisea storage database 3008 enabling the collected information to be locallystored rather than transmitted wirelessly to a remote location.

Referring now to FIG. 32, there is illustrated a particular example of ablock diagram of a particular apparatus for measuring the presence anconcentration of glucose using the orbital angular momentum of photonsof a light beam shined through a glucose sample. While the presentexample is with respect to the detection of glucose, one skilled in theart would realize that the example would be applicable to the detectionof the presence and concentration of any material. The process creates asecond-order harmonic with helical light beam using a non-linear crystalsuch as that described with respect to FIG. 25. The emission module 2402generates plane electromagnetic waves that are provided to an OAMgeneration module 3204. The OAM generation module 3204 generates lightwaves having an orbital angular momentum applied thereto using hologramsto create a wave having an electromagnetic vortex. The OAM twisted wavesare applied to the sample 3206 that is under study in order to detectthe glucose and glucose concentration within a sample. A rotatedsignature exits the sample 3206 in the manner described previously withrespect to FIGS. 28-29 and is provided to the matching module 3208. Thematching module 3208 will amplify the orbital angular momentum such thatthe observed concentrations may be calculated from the orbital momentumof the signature of the glucose. These amplified signals are provided todetection module 3210 which measures the radius of the beam w(z) or therotation of the image provided to the sample via the light beam. Thisdetected information is provided to the user interface that includes asensor interface wired or wireless Bluetooth or ZigBee connection toenable the provision of the material to a reading meter or a user phonefor the display of concentration information with respect to the sample.In this manner concentrations of various types of material as describeherein may be determined utilizing the orbital angular momentumsignatures of the samples under study and the detection of thesematerials or their concentrations within the sample determine asdescribed.

Provided the orthogonality of Laguerre polynomials, Laguerre Gaussianbeams exhibiting orbital angular momentum (OAM) have been determined asa basis for spatial division multiplexing (SDM) in communicationapplications using for example a mux-demux optical element design. OAMbeams are also of interest in quantum informatics. OAM also enables theprobing of solutions of chiral and non-chiral molecules.

FIG. 33 illustrates a further optical configuration for transmitting anddetecting information. The twisted nematic LCOS SLM 3302 implements a1024×768 array with 9 μm pitch and 8-bit resolution covering the visiblewavelength range (430-650 nm) and readily interfaced via a VGAconnection. A programmable SLM 3302 allows for the generation of avariety of engineered beams. A twisted nematic (TN) liquid crystal onsilicon (LCOS) SLM is particularly useful in realizing the hologramsthat modulate the phase front of the input plane wave 102 (FIG. 1) orGaussian beam. An SLM is computer addressable using common softwarepackages such as Matlab or Mathematica to define an arbitrarytwo-dimensional phase shift imprinted onto the beam input using, forexample, a hologram.

A collimated input beam is reflected off of a display appropriatelyencoded by a phase retarding forked gratings, or hologram. Thegenerating equation for the forked gratings may be written as a Fourierseries:

${T\left( {r,\varphi} \right)} = {\sum\limits_{m = {- \infty}}^{\infty}\;{t_{m}{\exp\left\lbrack {{- i}\;{m\left( {{\frac{2\pi}{D}r\;\cos\;\varphi} - {l\varphi}} \right)}} \right\rbrack}}}$

Where r and φ are the coordinates, l is the order of the vorticity and Dis the period of the rectilinear grating far from the forked pole. Theweights, t_(m), of the Fourier components of the phase grating may bewritten in terms of Bessel functions of integer order:t _(m)=(−i)^(m) J _(m)(kβ)exp(ikα).

Where kα and kβ bias and modulate the phase of the forked grating,respectively. Typically only a handful of terms of this series areneeded to generate the OAM beams. For example, success has been had withthe transfer pattern:

${T\left( {r,\varphi} \right)} = {\frac{1}{2} - {\frac{1}{2}{\sin\left( {{\frac{2\pi}{D}r\;{\cos\varphi}} - {l\varphi}} \right)}}}$

Referring now back to FIG. 33, there is illustrated the opticalconfiguration for detecting a unique signature of a signal passingthrough a sample under test 3303. The sample 3303 may be in a containeror in its naturally occurring state. At a high-level, the instrumentcomprises a Mach Zehnder interferometer. One arm of the interferometerpropagates a reference beam 3310. The reference beam 3310 is created bya laser 3304 generating a light beam including a plurality of planewaves that is transmitted through a telescope 3306. The plane wave lightbeam from the telescope 3306 passes through a first beam splitter 3308.The beam splitter 3308 generates the reference beam 3310 that isreflected from a mirror 3311 to an interfering circuit 3312. Thereference beam 3310 may be a plane wave or, with the addition of a lens,a spherical wavefront may be implemented. This arm is blocked foramplitude only measurements.

In a second arm, the split plane wave beam from the beam splitter 3308is combined at a beam combiner 3314 with the beam provided from thespatial light modulator 3302. The spatial light modulator 3302 providesa light beam including the forked hologram 3316. The beam combiner 3314combines the forked hologram beam 3318 from the SLM 3302 and a planewave beam 3320 from the laser 3304 to generate an OAM or otherorthogonal function twisted beam of a known signature. This beam isreflected through a series of mirrors 3322 and focused on a pinholeaperture 3324 before passing the beam having the known orbital angularmomentum through the sample under test 3303.

The sample twisted beam 3326 has been interfered at the signal combiner3312 with the reference beam 3310. This interfered image may then berecorded by a camera or recording device 3328. This provides a uniqueOAM signature 3330 that may be analyzed in order to detect materialswithin the sample under test 3303. As can be seen, the unique OAMsignature 3330 is different from the signature 3332 of the transmittedbeam. The manner in which the signature is altered will be more fullydescribed herein below.

In the second arm, the LCOS SLM 3302 is used to transform a collimatedplane wave input beam 3320 into an OAM encoded beam. The SLM 3302 isdriven by a Matlab programs on an extended laptop display to provide adisplay of a forked hologram of any l or p. Following the SLM 3302, thebeam is reflected through three mirrors 3322 to provide a sufficientdistance for the separation of the diffracted OAM modes such that apinhole iris aperture 3324 may select the desired mode to pass through asample under test 3303.

Several materials of interest may be detected with OAM signatures usingthe setup of FIG. 33. Examples of these materials include acetone,isopropyl alcohol, sucrose, amyloid-beta, and glucose in steam distilledwater. Spectroscopic grade soda lime glass cuvettes (1 cm×2.5 cm×3 cm)or larger custom-made circular cuvettes having BK7 cover glass in capsmay be utilized for containing the sample under test 3303.

The sample under test 3303 is mounted on a translation stage arranged toallow quick and repeatable positioning in and out of the beam patheither by movement of the sample or movement of the beam projectionapparatus. Additionally, back reflections from the sample services aremonitored carefully and blocked by irises so no spurious, secondaryinteractions occur. The optical power through samples is low (less than25 μW) to avoid any refractive index dependent thermal gradients in thesolution.

The insertion of wave plates, variable retarders and polarizers beforeand after the sample under test has not revealed any remarkable results.While glucose is well-known to have a polarimetric response at thesewavelengths, the concentration path length product is too small toproduce a notable shift in the state of polarization. This suggests thatthe OAM and glucose is a more pronounced response then polarimetry ofthe molecule.

Images 3330 of the beam at the output of the instrument are recordedusing the high-resolution DSLR camera 3328 that is securely mountedperpendicular to the beam propagation direction and remotely triggeredto prevent vibration or shift in the instrument. Measurement ofellipticity is performed using Photoshop and Matlab or similar types ofimage measuring and processing software or applications.

With this instrument, the change to an OAM state imparted on the inputbeam by a sample under test 3303 can be quantified in both intensity andphase. A series of experiments has been performed using primarilyaqueous glucose solutions. A 15% stock solution was diluted to a varietyof desired concentrations. Because the different isomers of the sugarinteract with each other before attaining equilibrium, a settling timeis required for a new or altered solution. Solutions were allowed toequilibrate overnight (approximately 15 hours), a time much longer thanthe recommended 2 hours, in a Cuvette that was capped to preventevaporation.

As mentioned previously with respect to FIG. 1, passing through thesample 3303 causes a unique OAM signature to be imparted to the lightbeam passing through the sample. This unique OAM signature provides anidentification of the presence of a material within the sample and ofthe concentration of the material within the sample. This unique OAMsignature includes a number of differences from the OAM signal signaturethat is input to the sample 3303. The unique OAM signaturecharacteristics are illustrated in FIGS. 34-36. FIG. 34 illustrates themanner in which the ellipticity of the OAM intensity diagram changesafter passing through the sample 3303. Initially, as illustrated at3402, the intensity diagram has a substantially circular shape from theplane wave OAM beam before passing through the sample 3303. Afterpassing through the sample 3303, the intensity diagram has a much moreelliptical shape as illustrated generally at 3404. This elliptical shapeis a unique characteristic that is different depending upon a materialbeing detected and the concentration of the substance being detected. Bydetecting the ellipticity of the intensity diagram, a determination maybe made of the presence of a particular material within the sample.

FIG. 35 illustrates a further characteristic of the OAM signature thatmay be altered by passing through a sample 3303. In this case, thecenter of gravity of the intensity diagram has been shifted. Position3502 illustrates the initial position of the center of gravity of theintensity diagram before passing through a sample 3303. After passingthrough the sample 3303, the center of gravity moves to location 3504that is a noticeable shift from the original position prior to passingthrough the sample. The shift is uniquely affected by differentmaterials. Thus, the shift in center of gravity may also be used as anOAM distinct signature characteristic with the center of gravity shiftindicating the presence of a particular material and the concentrationof the material. Based upon an analysis of the shift in the center ofgravity of the intensity diagram, a determination of the presence and/orconcentration of a material may be made.

A final distinct OAM signature characteristic is illustrated in FIG. 36.In this case, the major axis 3602 of the intensity diagram ellipseshifts from a first position 3602 to a second position 3604 over anangle θ 3606. The major axis of the intensity diagram ellipse rotatesfrom a position 3602 to position 3604 based upon the material beingdetected. The angle θ is uniquely associated with a particular substanceand concentration of the substance being detected. Thus, a material maybe detected based upon a determined angle θ within the intensitydiagram.

A mathematical model may be used to represent the unique OAM signaturesprovided by each of changes in eccentricity, shift or translation of thecenter of gravity in rotation of the axis. The change in eccentricitymay be represented by:

$\left. {circle}\Rightarrow{x^{2} + y^{2} + z^{2}}\Rightarrow{\left\lbrack {x\mspace{14mu} y\mspace{14mu} z} \right\rbrack\begin{bmatrix}x \\y \\z\end{bmatrix}} \right.$$\left. {3\text{-}{dimensional}\mspace{14mu}{ellipse}}\Rightarrow{{\left\lbrack {x\mspace{14mu} y\mspace{14mu} z} \right\rbrack\begin{bmatrix}\frac{1}{a^{2}} & 0 & 0 \\0 & \frac{1}{b^{2}} & 0 \\0 & 0 & \frac{1}{c^{2}}\end{bmatrix}}\begin{bmatrix}x \\y \\z\end{bmatrix}} \right.$Where a, b, c are dimensions of the ellipse.

The change in the center of gravity may be represented by a shift ortranslation in space of a vector v according to the matrix:

$\left. {translation}\Rightarrow\begin{bmatrix}1 & 0 & v_{x} \\0 & 1 & v_{y} \\0 & 0 & v_{z}\end{bmatrix} \right.$

The rotations of the axis may be represented by a series of matricesshowing rotations in 3-different orientations:

$\underset{{Rotation}\mspace{14mu}{by}\mspace{14mu}\alpha}{\begin{bmatrix}1 & 0 & 0 \\0 & {\cos\;\alpha} & {{- \sin}\;\alpha} \\0 & {\sin\;\alpha} & {\cos\;\alpha}\end{bmatrix}}\underset{{Rotation}\mspace{14mu}{by}\mspace{14mu}\beta}{\begin{bmatrix}{\cos\;\beta} & 0 & {\sin\;\beta} \\0 & 1 & 0 \\{{- \sin}\mspace{11mu}\beta} & 0 & {\cos\;\beta}\end{bmatrix}}\underset{{Rotation}\mspace{14mu}{by}\mspace{14mu}\gamma}{\begin{bmatrix}{\cos\;\gamma} & {{- \sin}\;\gamma} & 0 \\{\sin\;\gamma} & {\cos\;\gamma} & 0 \\0 & 0 & 1\end{bmatrix}}$

In an example illustrated in FIGS. 37A and 37B there is shown theapplication of an OAM beam to a sample consisting only of water (FIG.37A) and of water including a 15% glucose concentration (FIG. 37B). Anl=7 OAM beam at 543 nm is propagated through a 3 cm Cuvette of onlywater to provide the intensity diagram illustrated in FIG. 37A. Theintensity diagram illustrated in FIG. 37B is provided when the l=7 OAMbeam passes through a 15% glucose solution in water. The OAM signaturemanifests itself as an induced ellipticity on the ordinary circular beamamplitude illustrated in the intensity diagram of FIG. 37A. The distinctsignature effect may also be observed in phase diagrams such as thatillustrated in FIGS. 38A and 38B. FIGS. 38A and 38B illustrateinterferograms of an l=2 OAM beam at 633 nm propagating through a 3 cmcuvette of water (FIG. 38A) and a 3 cm cuvette of 15% glucose in water(FIG. 38B). In this particular interference, the reference beams havethe same spherical wave fronts. This is why essentially spiral patternis observed in the phase measurements. Note in particular, the torsionalshift in one of the 2 spirals of the phase front of the samplepropagating through the glucose solution. The shift in the spiralpattern is the signature of the interaction in this experiment.

An unperturbed OAM mode propagates through several meters of free space.Glucose samples appear to impart a phase perturbation on an OAM beamcausing the OAM mode to topologically be involved in the propagationdirection. This effect allows for more sensitive metrology. FIG. 39shows the amplitude of an OAM beam and FIG. 40 shows the phase of an OAMbeam. The beam is an OAM f=beam and is perturbed when passing through a3 cm Cuvette of a 5% glucose solution and a plane four meters beyond theCuvette. The ellipticity of the beam is much more pronounced in bothamplitude and phase measurements.

The OAM signature is nonlinear with respect to glucose concentrationsand under some conditions, appears to be somewhat periodic withconcentration. The ellipticity as a function of glucose concentration isplotted in FIG. 41 using a 3 cm Cuvette, OAM modes l=5, 6, 7, forconcentrations of glucose between 5% and 9% in water. Though thepreliminary data is noisy, the trend persists over several OAM modes.

There is a broad absorption band for glucose centered at approximately750 nm, with a FWHM (Full Width Half Maximum), as understood by a personof skill in the art, of approximately 250 nm. Given that the 543 nmabsorbance of glucose is 4 times smaller than that for 633 nm, it isinteresting that the formal wavelength provides a stronger OAM response.This suggests the interaction is based on the real part of thesusceptibility, χ′, rather than its imaginary part, χ″. We note as wellthat in a separate polarimetry characterization of glucose, using samplecells as long as 20 cm, we measured a 50% larger specific rotation at543 nm than at 633 nm. In the OAM work, however, we found no discernablechange in the effect with polarization, nor did we observe a change inthe state of polarization of the beam through the 3 cm samples. This isin keeping with the previous polarization studies of OAM with chiralmolecules.

As a check for whether the vorticity of the OAM beam was important forthe effect, and annulus was used to project a simple ring of lightthrough a glucose sample. The annulus pattern was printed on atraditional plastic transparency sheet and illuminated with a magnifiedand collimated 543 nm laser beam. As can be seen in FIGS. 42A-42C, nodistortion or signature was observed through Cuvette's of water (FIG.42B) or Glucose (FIG. 42C) solution. Varying the ring diameter did notchange these no results, even for diameters larger than the typical OAMbeam. When the annulus diameter was larger than the Cuvette, obviousclipping was observed. The power level of the beams in this test was asmuch in order of magnitude higher than in the OAM experiments. Thus, anythermal effects would have been accentuated.

Since aqueous solutions of glucose were used in the experiments, thestudy of propagation of OAM in water is relevant. Steam distilled water,the solvent used in dilution, was placed in clean new cells of thevariety of links and cross-sections and propagation of a variety of OAMbeams through this medium was measured. No discernible differences wereobserved among an OAM mode propagated through a dry cell, a sample ofpath length 0.5 cm and a sample of 8 cm of water.

Another null result was observed in an experiment were in an OAM beamwas propagated through a liquid crystal that variable retarder. In FIG.43, reference Nos. 4302, 4304 and 4306 show an l=7 OAM mode at theoutput of a variable wave plate for differing drive voltages between 0.1V and 6 V.

It is been noted that the eccentricities of the intensity imagesproduced by shining orthogonal function processed beam through a samplecan have variances due to a number of differing factors. FIG. 44illustrates an example wherein a light beam produced by a laser 4402 isaltered by a hologram provided by an SLM 4404 to generate an OAM twistedbeam 4406. The OAM twisted beam in addition to being altered by OAMfunctions may also be processed using Hermite Gaussian functions,Laguerre Gaussian functions or any other type of orthogonal function.The OAM twisted beam is focused through a system 4408 of lenses andmirrors to direct the beam through a mode sorter 4410. The beam isseparated into its different modes when regenerated at mode sorter 4412and the intensity images may be registered by a camera 4414.

The beam from the laser 4402 has an inherent eccentricity ofapproximately 0.15. As illustrated in FIG. 45, there are illustratedvarious OAM modes produced by the SLM in column 4502 for l=5, 4, 3,2, 1. As can be seen, there are differences between the eccentricity ofthe modes produced by the SLM, and the eccentricity of the modesregenerated by the second mode sorter 4412.

Measurements of eccentricity are performed using Photoshop and Matlab toidentify the specific signatures. Referring now to FIG. 46, there isillustrated an example of an ellipse 4602 having a radius “a” along itslong axis, a radius “b” along a short axis and a distance “c” to thefoci 4604 of the ellipse. The eccentricity of the ellipse is representedby the equation eccentricity=c/a. The eccentricity varies from 0 to 1with 0 representing a circle and 1 representing a line. The eccentricityequation is calculated according to the following equations:

$U_{xx} = {{\frac{1}{N}{\sum\limits_{i = 1}^{\;^{N}}\; x_{i}^{2}}} + \frac{1}{12}}$$U_{yy} = {{\frac{1}{N}{\sum\limits_{i = 1}^{\;^{N}}\; y_{i}^{2}}} + \frac{1}{12}}$$U_{xy} = {\frac{1}{N}{\sum\limits_{i = 1}^{\;^{N}}\;{y_{i}x_{i}}}}$${common} = \sqrt{\left( {U_{xx} - U_{yy}} \right)^{2} + {4U_{xy}^{2}}}$${2a} = {2\sqrt{2}\sqrt{{U_{xx}U_{yy}} + {common}}}$${2b} = {2\sqrt{2}\sqrt{{U_{xx}U_{yy}} - {common}}}$$c = \sqrt{a^{2} - b^{2}}$ ${Eccentricity} = \frac{c}{a}$where x_(i) is the x location of the pixels in the ellipse; y_(i) is they locations of the pixels in the ellipse; and N is the number of pixelsin the ellipse.

It is been found that the eccentricity is greater than 0 when no sampleis present within the cuvette. A number of factors contribute to thenonzero eccentricity. OAM twisted signals have been found to providedifferent eccentricities based upon a number of different factors thatmay affect the index of refraction. These factors include things such asthe sample distribution of the material within the cuvette due togravity, the distance of the camera from the spatial light modulator andthe camera angle of the camera from the spatial light modulator. Otherfactors affecting the eccentricity are the cuvette positioning, theindex of refraction changes do to the sample, the cuvette shape and thebeam incidence and exit angle from the cuvette.

Several image processing factors have also been determined not to causechanges that are outside the margin of error. Changes based on softwareprocessing errors, a circular mask that is not OAM, the sample sittingtime or the sample interaction with the glass or plastic comprising thesample container may provide eccentricity changes, but the changes arenot due to optical impairments caused by the cuvette orientation, cameraalignment, etc. These factors do produce some changes in eccentricity,but they are within the margin of error and the majority of theeccentricity change is based on the signature of the molecule beingdetected.

Referring now to FIG. 47, there is illustrated a flow diagram foranalyzing intensity images taken by the camera 4414. The intensity imagehas applied thereto threshold double precision amplitude to enable thering to be clearly seen without extra pixels outside of the ring at step4702. Next at step 4701, both columns and rows are scanned along for theentire image. The peaks of the two largest hills and their locations aredetermined at step 4706. An ellipse is fit at step 4008 for all peaklocations found. Finally, at step 4710, a determination is made of themajor and minor axis of the ellipse, the focal point of the ellipse, thecentroid, eccentricity and orientation of the ellipse.

FIG. 48 illustrates an ellipse fitting algorithm flowchart. The X and Ypixel locations are input at step 4802 for all peaks that are found. Aninitial guess is provided at step 4804 for the conic equationparameters. The conic equation parameters comprise parameters A, B, C, Dand E for the equation Ax²+By²+Cx+Dy+E=0. The conjugate gradientalgorithm is used at step 4806 to find conic equation parameters thatprovide an optimal fit. An orientation of the ellipse is determined atstep 4808 and moved to determine the major and minor axis. Thedetermination of step 4808 is determined according to the equation

$\varnothing = {\frac{1}{2}\tan^{- 1}\frac{B}{C - A}}$The ellipse orientation is returned at step 4810 to determine thecentral point of the ellipse. Finally, at step 4812, a determination ismade if the conic equation represents an ellipse. For an ellipseparameters A and B will exist and have the same sign but will not beequal. Based upon this analysis it is been determined that lateral shiftof up to 1 mm can cause significant changes in the measured eccentricitydue to clipping of up to 0.2.

It will be appreciated by those skilled in the art having the benefit ofthis disclosure that this system and method for the detection of thepresence of materials within a sample based on a unique signature. Itshould be understood that the drawings and detailed description hereinare to be regarded in an illustrative rather than a restrictive manner,and are not intended to be limiting to the particular forms and examplesdisclosed. On the contrary, included are any further modifications,changes, rearrangements, substitutions, alternatives, design choices,and embodiments apparent to those of ordinary skill in the art, withoutdeparting from the spirit and scope hereof, as defined by the followingclaims. Thus, it is intended that the following claims be interpreted toembrace all such further modifications, changes, rearrangements,substitutions, alternatives, design choices, and embodiments.

What is claimed is:
 1. An apparatus for detecting a presence of apredetermined material within a sample, comprising: signal generationcircuitry for generating a first signal having a first distinctsignature including a first eccentricity of a mode intensity, a firstshift in a center of the mode intensity and a first rotation of anellipsoidal intensity output of the mode intensity and applying thefirst signal to the sample; a detector for receiving the first signalafter the first signal passes through the sample, for detecting a seconddistinct signature including a second eccentricity of the modeintensity, a second shift in the center of the mode intensity and asecond rotation of the ellipsoidal intensity output of the modeintensity and for determining the presence of the predetermined materialwithin the sample based on the detected second distinct signature withinthe first signal received from the sample, the detector providing anoutput of an indication of the presence of the predetermined materialresponsive to the determination.
 2. The apparatus of claim 1, whereinthe signal generation circuitry applies the first distinct signatureusing a spatial light modulator.
 3. The apparatus of claim 1, whereinthe signal generation circuitry applies the first distinct signatureusing a digital light processor.
 4. The apparatus of claim 1, whereinthe signal generation circuitry applies the first distinct signatureusing a hologram.
 5. The apparatus of claim 1, wherein the signalgeneration circuitry applies the first distinct signature using anamplitude mask.
 6. The apparatus of claim 1, wherein the signalgeneration circuitry applies the first distinct signature using a phasemask.
 7. The apparatus of claim 1, wherein the detector furtherimplements Photoshop to identify the second eccentricity of the modeintensity.
 8. The apparatus of claim 1, wherein the detector implementsMatlab to identify the second distinct signature.
 9. The apparatus ofclaim 1, wherein the detector negates effects of at least one of sampledistribution due to gravity, angle of camera recording the modeintensity to the sample, a container holding the sample, an angle ofincidence of the first signal to the sample and an angle exit of thefirst signal from the sample to detect a change in an eccentricity ofthe mode intensity.
 10. The apparatus of claim 1, wherein the detectorfurther includes circuitry for determining a phase of the first signalafter it passes through the sample, wherein the circuitry determines thephase by interfering the first signal having the second distinctsignature therein with the first signal having plane waves therein. 11.A method for detecting a presence of a predetermined material within asample based upon a unique orbital angular momentum signature,comprising: generating a first signal having a first distinct signatureincluding a first eccentricity of a mode intensity, a first shift in acenter of the mode intensity and a first rotation of an ellipsoidalintensity output of the mode intensity; applying the first signal to thesample; receiving the first signal after the first signal passes throughthe sample; detecting within the received first signal a second distinctsignature including a second eccentricity of the mode intensity, asecond shift in the center of the mode intensity and a second rotationof the ellipsoidal intensity output of the mode intensity; determiningthe presence of the predetermined material within the sample based onthe detected second distinct signature within the first signal receivedfrom the sample; and providing an output of an indication of thepresence of the predetermined material responsive to the determination.12. The method of claim 11, wherein the step of generating furthercomprises the step of generating the first distinct signature using aspatial light modulator.
 13. The method of claim 11, wherein the step ofgenerating further comprises the step of generating the first distinctsignature using a digital light processor.
 14. The method of claim 11,wherein the step of generating further comprises the step of generatingthe first distinct signature using a hologram.
 15. The method of claim11, wherein the step of generating further comprises the step ofgenerating the first distinct signature using an amplitude mask.
 16. Themethod of claim 11, wherein the step of generating further comprises thestep of generating the first distinct signature using a phase mask. 17.The method of claim 11, wherein the step of detecting further comprisesimplementing Photoshop to identify the second eccentricity of the modeintensity.
 18. The method of claim 11, wherein the step of detectingfurther comprises detecting the second distinct signature using Matlab.19. The method of claim 11, wherein the step of detecting comprisesnegating effects of at least one of sample distribution due to gravity,angle of camera recording the mode intensity to the sample, a containerholding the sample, an angle of incidence of the first signal to thesample and an angle exit of the first signal from the sample to detect achange in an eccentricity of the mode intensity.
 20. The method of claim11, wherein the step of detecting further comprises: interfering thefirst signal having the second distinct signature therein with the firstsignal having plane waves therein; and determining a phase of the firstsignal after it passes through the sample responsive to the interferedfirst signal.